Intracranial pressure (ICP) monitoring and control is a vital component of neurosurgical management for individuals with brain edema due to a variety of maladies, including tumor, encephalitis, meningitis, and hydrocephalus [Ivan, Intracranial Pressure Monitoring with Fiberoptic Transducer for Children, CHILD'S BRAIN 7: 303-313]. Shunting systems provide for pressure management of ICP but are often subject to failure due to blockage and other faults. The ability to monitor ICP enables improved diagnosis and response to shunting failure, in addition to overall improved management of abnormal ICP conditions.
Systems exist which monitor ICP either through existing fluid shunting systems or through independent intraventricular access tubing. Because most of these systems are not fully implantable, the attached wires make continuous patient monitoring difficult, and cables restrict patient movement. In addition, the potential for infection through the interfacial boundary to the exterior of the patient is great with such partially implantable systems. Often, due to the simplicity of their design, most partially implantable systems are inherently inaccurate and, even if initially calibrated, easily become decalibrated.
Fully implantable monitoring systems are available but suffer from a number of serious drawbacks. Currently available systems rely solely upon internally located power supplies, i.e., batteries. However, once the batteries are exhausted, the device fails. Furthermore, currently available systems do not allow the simultaneous use of multiple pressure sensors or other physiological sensor combinations. Built-in programmable alarm capabilities which can warn of either mechanical/electronic problems or more serious physiological problems are also lacking in currently available monitoring systems.
Additionally, presently available implantable systems typically incorporate slow and noisy data transmission methods that are prone to interference from many sources, including nearby medical electronic equipment and systems.
Thus there is a need for a totally implantable ICP monitor which is not completely dependent upon an exhaustible internal power supply.
There is a further need for an implantable ICP monitor which can couple to existing fluid shunting systems as well as other internal monitoring probes.
There is still a further need for an implantable ICP monitor which is accurate and reliable and will not become decalibrated, even over extended periods of time.